I suggest you to check if your computer meets the minimum system requirements to run A.V.A:
- OS: Windows XP, Windows Vista or Windows 7;
- CPU: Pentium 4 2.4G dual-core;
- Free Hard Drive Space: 5GB;
- Video Card: Geforce 7600GT graphics card or equivalent.
If the requirements are fulfilled, I suggest you to uninstall and reinstall the game. You can find a download link on the official web page. Also, you need to know that IP addresses from certain countries can no longer access the game.